Leaving the App Store and third-party applications as the only unfinished business for the second generation iPhone. The App Store also is expected to debut Friday morning.

We’ve been given a taste of what to expect after Apple’s World Wide Developers Conference last month, when we saw programs such as Loopt, Twitterific, Typepad, the Associated Press Mobile News Network, and other apps in action.

But what else is going on out there? What can we expect when the App Store doors are thrown open for business?

More than the iPhone 3G hardware, more than the MobileMe service, the App Store and third-party applications is where the action is.

Thanks to The Unofficial Apple Weblog, who more than any other Web resource, has kept tabs on upcoming iPhone apps since the developers conference in early June. Here is a sampling of apps from TUAW, and others. It is by no means comprehensive as we expect to see all kinds of applications — from super polished to rough around the edges, from the big guys to the little guys — come opening day.

Utilities

What to expect: Everything from remote control to security apps. This will be one of the most popular areas in the App Store.

1password: an iPhone version of the popular desktop password organizer. If it’s anywhere near the quality of the desktop app, expect this one to be super.

From WebIs: developer of Windows Mobile apps like Pocket Informant and eWallet is readying apps for the iPhone. I’ve used Pocket Informant and eWallet in my Windows Mobile days (shudder), and the programs were a heck of a lot better than anything Microsoft developed.

AirRemote: turn the iPhone (and Touch) into a television remote control; needs additional hardware and it’s costly. One of my pet peeves is poorly designed all-in-one remote controls, including Logitech, but you’ll shell out about $250 to try this. And what happens when you take your iPhone with you when you leave the house?

Productivity

What to expect: Fierce competition between To Do, Getting Things Done (GTD), and personal task management programs. How well these integrate the phone, the Web, and the desktop is key.

And there will be tons more of these come opening day. We’ll be testing free games and buying the ones we think we might like for weeks.

GPS/Location

What to expect: Other than the faster 3G network, the most anticipated hardware change to the iPhone is the addition of GPS. Early reviews of this functionality have been mixed. We’ll see a steady stream of GPS and location-based apps over the next several weeks/months as these are complex to develop in mostly unchartered waters.

G-Spot: a compass and tool to determine your latitude and longitude using the iPhone 3G‘s built-in GPS antenna; you’ve got to love the tongue-in-cheek name (see other apps from developer PosiMotion)

NearPics: see pictures taken where you are at the time (from the MacBox)

Health and Fitness

What to expect: a promising if under-publicized category. Yet health and fitness apps may be some of the best, and most used, apps for the iPhone as people have their phones with them most of the day — great for recording how many steps you walk, tracking what you eat, and what those healthy ingredients are for tonight’s dinner.

What to expect: We’re not sure. eBook readers are avid fans of Amazon’s Kindle and Sony’s eReader, among other devices, but the general population is a long way from accepting electronic books. Having the ability to read eBooks on the iPhone may be convenient, but it’s doubtful it will take off unless the major publishers get behind it.

It will be exhilarating to finally have third-party apps on the iPhone, hopefully working in conjunction with MobileMe or other cloud solutions. But, to be honest, this is a dangerous place for Apple and the iPhone to be at this time.

Why?

Battery life. Just ask Pogue, Mossberg, and Baig, who universally complained about iPhone 3G‘s lack of battery life — about five hours compared with eight hours on the original iPhone.

Using robust third-party applications, and goofing around with free games and oddball apps, will be intoxicating and addictive. Just keep an eye on that battery icon in the upper right corner.

last100 is edited by Steve O'Hear. Aside from founding last100, Steve is co-founder and CEO of Beepl and a freelance journalist who has written for numerous publications, including TechCrunch, The Guardian, ZDNet, ReadWriteWeb and Macworld, and also wrote and directed the Silicon Valley documentary, In Search of the Valley. See his full profile and disclosure of his industry affiliations.